|
KMID : 0043319890120020128
|
|
Archives of Pharmacal Research
1989 Volume.12 No. 2 p.128 ~ p.134
|
|
|
Increase in Na+-Ca2+ Exchange Activity in Sarcolemma Isolated from Mesenteric Arteries of Spontaneously Hypertensive Rats
|
|
Lee SW
Lee JS/Park YJ/Park IS
|
|
|
Abstract
|
|
|
|
Na+-Ca2+ exchange process in sarcolemmal vesicles isolated from mesenteric arteries of Wistar-Kyoto normotensive(WKY) and spontaneously hypertensive rats(SHR) was investigated. The sarcolemmal fractions isolated after homogenization and sucrose density gradient centrifugation were enriched with 5’’-nucleotidase and ouabain sensitive, K+-dependent phosphatase activities. When the vesicles were loaded with Na+, a time dependent Ca2+ uptake was observed. However, very little Ca2+ uptake was observed when the vesicles were loaded with K+, or Ca2+ uptake of the Na+-loaded vesicles was carried out in high sodium medium so that there was no sodium gradient. When the vesicles loaded with Ca2+ by Na- -Ca2+ exchange were diluted into potassium medium containing EGTA, Ca2+ was rapidly released from the vesicles. Na+-dependent Ca2+ uptake was increased in SHR compared to WKY, but passive efflux of preaccumulated Ca2+ from the vesicles was decreased in SHR. The data indicate that the membrane vesicles of rat mesenteric arteries exhibit Na+-Ca2+ exchange activity. It is also suggested that changes of this process in vascular smooth muscle cell membrane of SHR may be involved in higher intracellular Ca2+ concentration and higher basal tone in SHR.
|
|
|
KEYWORD
|
|
|
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
  
|